Groundwater monitoring during underground coal gasification

Dyk, J.C. van; Brand, J.F.; Strydom, Christien A.; Waanders, F.B.

doi:10.17159/2411-9717/2018/v118n10a2

Cited by 1 publication

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“…However, some authors have made general observations. Van Dyk and Keyser, [31] found that low ash melting temperatures were generally accompanied by high CaO and high Fe 2 O 3 . Song et al [32] investigated the effect of coal ash composition on AFTs.…”

Section: A Carbonaceous Materials Characterizationsmentioning

confidence: 99%

Damring Formation During Rotary Kiln Chromite Pre-reduction: Effects of Pulverized Carbonaceous Fuel Selection and Partial Pellet Melting

Staden

Beukes

Zyl

et al. 2018

Metall Mater Trans B

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Electricity consumption is the largest cost contributing factor in the production of ferrochrome. Currently the pelletized chromite pre-reduction process (solid-state reduction of chromite) is the process option with the lowest specific electricity consumption (MWh/ton). In this process, pelletized chromite is fed into a rotary kiln at 1573 K (1300°C), where partial pre-reduction takes place. Damring formation (material build-up) in the rotary kiln causes routine shutdowns, resulting in loss of revenue. The damring formation is possibly caused by melting of the ash of the pulverized coal used to fire the kiln and/or the partial melting of the chromite pellets. Ash fusion temperatures of twenty different samples were evaluated to assess the temperature at which the pulverized coal ash will start to contribute to damring formation. Sessile drop tests were used to assess the softening behavior of different ore types (e.g., UG2, MG, and LG metgrade), as well as softening of composite chromite pellets made from these ores. Actual damrings were also analyzed using scanning electron microscopy with energy dispersive X-ray spectroscopy. Results indicate that it is mainly the pulverized coal ash that will contribute to damring formation, and not ore or pellet softening. Multiple-linear regression was used to derive equations to predict the ash fusion temperatures of the pulverized coal ash, which can be used by ferrochrome producers to optimize pulverized coal selection.

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Section: A Carbonaceous Materials Characterizationsmentioning

confidence: 99%